Sunday, April 30, 2006

General Dynamics F-111

In June 1960 the USAF issued a specification for a long-range interdiction/strike aircraft able to penetrate Soviet air defenses at very low altitudes and very high speeds to deliver tactical nuclear weapons against crucial Soviet targets like airfields and supply depots. Included in the specification were a low-level speed of Mach 1.2, a high-altitude speed of Mach 2.5, a combat radius of 890 mi (1,430 km), good short-field performance, and a ferry range long enough to reach Europe unrefueled.The U.S. Navy, meanwhile, had since 1957 been searching for a long-range, high-endurance interceptor to defend its carrier groups against the new generation of Soviet jet bombers, which by then were being armed with huge anti-ship missiles with nuclear warheads.The program was dubbed TFX (Tactical Fighter Experimental). The TFX design eventually emerged as an aircraft in the 20-ton (empty) class with a maximum take-off weight of almost 50 tons. It had been intended to use titanium for large portions of the airframe to save weight, but this proved prohibitively expensive. The TFX was powered by two afterburning Pratt & Whitney TF30-P-100 turbofans in the 80 kN class. The shoulder-mounted wings were attached to a pair of giant pivots, allowing it to take off, land, and loiter with a modest 16° sweep (for maximum lift and minimum landing speed), cruise at high subsonic speeds with a 35° sweep, or sweep back to a 72.5° maximum for fast supersonic dashes at more than Mach 2. Despite its high maximum speed, its modest thrust fraction (thrust-to-weight ratio) made early versions somewhat underpowered, exacerbated by compressor stalls and other engine problems that forced a hasty redesign of the engine inlets.First flight of the F-111A, as the USAF version was designated, was 21 December 1964, and entry into service with the USAF began 18 July 1967.The Navy version, the F-111B (visually distinguishable from all other variants due to its noticeably shorter nose), was cancelled in December 1968 to be replaced by the F-14 Tomcat, but other F-111 variants went on to serve with the USAF through the mid-1990s, performing with distinction in the 1991 Gulf War. Although the United Kingdom had expressed interest in the program in 1965 in preference to the home grown BAC TSR-2, the British order for the F-111 was cancelled, and the F-111's only export customer was the Royal Australian Air Force.Currently the Royal Australian Air Force is the only operator of the F-111 and continues to upgrade the aircraft with modern avionics as well as modern weapon systems. To replace the elderly and obsolescent Douglas EB-66, in 1972 the USAF contracted Grumman to convert some existing F-111As into electronic warfare/ECM aircraft. The Air Force had considered the Navy Grumman EA-6B Prowler, but was reluctant to adopt a Navy aircraft.A contract to develop the EF-111A was awarded to Grumman in 1974, modifying existing -A airframes. The first fully equipped model flew on 10 March 1977,known then as the "Electric Fox", and deliveries to combat units began in 1981. A total of 42 conversions were completed, the last delivered by the end of 1985. The EF-111A received the official popular name Raven, although in service it acquired the nickname "Spark 'Vark". Specifications (F-111)General characteristics

Mikoyan-Gurevich MiG-23 “Flogger”

The Mikoyan-Gurevich MiG-23 (NATO reporting name 'Flogger') is a variable geometry, swept-wing fighter aircraft, originally built by the Mikoyan-Gurevich design.DevelopmentThe MiG-23's predecessor, the MiG-21 Fishbed, was fast and agile, but very limited in its operational capabilities.The MiG-23 was to be a heavier, more powerful machine designed to remedy these deficiencies, and, it was hoped, rival Western aircraft like the F-4 Phantom. A major design consideration was take-off and landing performance. The Soviet Air Force demanded that the new aircraft have a much shorter take-off run. Also, low-level speed and handling was to be improved over MiG-21The second prototype, known as 23-11, featured variable-geometry wings which could be set to angles of 16, 45 and 72 degrees, and it was clearly more promising. The order to start series production of the MiG-23 was given in December 1967. Service careerThe first MiG-23s to see combat were export variants with many limitations. For example, MiG-23MS lacked such a basic system as radar warning receiver. In addition, compared to MiG-21, the aircraft was mechanically complex and expensive. In the 1980s, an improved MiG-23ML was widely exported, which performed better and was met with more enthusiasm by its users.It is known that some number of air victories were scored by MiG-23s in the Iran-Iraq War. Cuban MiG-23MLs and South African Mirage F.1s had several encounters during Angolan War. Soviet MiG-23MLDs and Pakistani F-16s clashed a few times during Afghan-Soviet War; one F-16 was reportedly lost in a friendly fire incident (according to the Pakistanis), but Russian reports claim the F-16 was shot down by a MiG-23MLD.Western pilots who flew the MiG-23 said its handling was similar to something between the F-4E and the Panavia Tornado in some parts of the flight envelope, and more like the F-105 in others. Soviet manuals considered the MiG-23MLD's performance and handling superior to that of the F-4E and, in some parts of the flight envelope, better than the F-16A's, but admitted that the F-15 has an overwhelming superiority over the MiG-23 family. The Israelis tested the MiG-23 and found that it had better acceleration than the F-16 and F-18. Overall, the MiG-23 represents the final incarnation of the late 1960s fighter technology which, despite being developed close to its full potential, was quickly overtaken by next generation. The MiG-23's closest contemporaries are perhaps the Mirage F.1 and Saab Viggen, which ended up with fairly similar careers.Specifications (MiG-23MLD Flogger-K)

Lockheed U-2 (TR-1)

The U-2, nicknamed Dragon Lady, is a single-seat, single-engine, high-altitude Surveillance aircraft flown by the United States Air Force. It provides continuous day and night, high-altitude (70,000 ft, 21,000 m plus), all-weather surveillance of an area in direct support of U.S. and allied ground and air forces. It also provides critical intelligence to decision-makers through all phases of conflict, including peacetime indications and warnings, crises, operations other than war, and major theater war. The aircraft came to public attention during the U-2 Crisis when pilot Francis Gary Powers was shot down over Soviet territory on May 1, 1960. On October 14, 1962, it was a U-2 from the 4080th Strategic Reconnaissance Wing that photographed the Soviet military installing nuclear warhead missiles in Cuba, precipitating the Cuban missile crisis.Initially, Clarence "Kelly" Johnson adapted the F-104 Starfighter, replacing the low aspect ratio blade wings with extremely large glider type wings as a starting point. High aspect ratio wings give the U-2 some glider-like characteristics. The aircraft is extremely challenging to fly, not only due to its unusual landing characteristics, but also because of the extreme altitudes it can reach. When flying the U-2A and U-2C models (no longer in service) close to its operational ceiling, the maximum speed (critical mach) and the minimum speed (stall speed) approach the same number, presenting a narrow window of safe airspeed the plane must maintain. In these models over 90% of a typical mission is flown within five knots of stall speed.The U-2 is considered one of the most challenging aircraft in the military inventory to fly and requires a high degree of airmanship from its pilots. Its large wingspan and resulting glider-like characteristics make the U-2 highly sensitive to crosswinds. This sensitivity, and the aircraft's tendency to float over the runway, makes the U-2 notoriously difficult to land. Typically, a second U-2 pilot, designated as the mission's backup pilot and referred to as the "mobile," waits in a high-performance chase car at the end of the runway as the aircraft makes it landing approach. As the U-2 passes, the chase car follows it at high speed, with the mobile calling out the aircraft's altitude via radio to the pilot. When the aircraft's main landing gear is within approximately two feet of the runway surface the pilot deploys spoilers located on the top of the wings to reduce lift (spoiling the lift and increasing the stall speed by 2 knots). Retractable stall strips on the wings' leading edges that are deployed prior to entering the landing phase help to produce equal stalling effects. This is done to minimize wing drop, assisting in aircraft control particularly during strong cross winds. The aircraft carries a variety of sensors. The U-2 is capable of simultaneously collecting signals and imagery intelligence. Imagery intelligence sensors include either wet film photo, electro-optic or radar imagery -- the latter from the Raytheon ASARS-2 system. It can use both line-of-sight and beyond-line-of-sight data links.The U-2 project was initiated in the early 1950s by the CIA which desperately wanted accurate information on the Soviet Union. Overflights of the Soviet Union with modified bombers started around 1951, but they were vulnerable to antiaircraft fire and fighters, and a number of border flights were shot down. It was thought a high altitude aircraft such as the U-2 would be hard to detect and impossible to shoot down. Lockheed Corporation was given the assignment with an unlimited budget and a short time frame. Its Skunk Works, headed by Clarence "Kelly" Johnson performed remarkably, and the first flight occurred in August 1955. Kodak also developed new cameras, which worked well. It made its first over-flight of the Soviet Union in June 1956.Data for Lockheed U-2R

Saab JAS-39 "Gripen"

The Saab JAS-39 "Gripen" is designed for the expected high demands on flying performance, flexibility, effectiveness, survivability, and availability for the future of air combat. The designation JAS stands for Jakt (Fighter), Attack (Attack), and Spaning (Reconnaissance), indicating that the Gripen is a multirole aircraft that can fulfill each mission type equally well.Flying properties and performance are optimised for fighter missions with high demands on speed, acceleration and turning performance. The combination of delta wing and canards gives the JAS 39 Gripen very good take off and landing performance and superb flying characteristics. The totally integrated avionics makes it a "programmable" aircraft. With the built in flexibility and development potential the whole JAS 39 Gripen system will retain and enhance its effectiveness and potential well into the 21st century.Gripen affords far more flexibility than earlier generations of combat aircraft, and its operating costs will only be about two thirds of those for Viggen. This is especially impressive as the Gripen is a more capable aircraft, with a low purchase price.The specifications for the Gripen required the ability to operate from 800 m runways. Early on in the programme, all flights from Saab's facility in Linköping were flown from within a 9 m x 800 m outline painted on the runway. Stopping distance is reduced by extending the relatively large airbrakes; using the control surfaces to push the aircraft down enabling the wheel brakes to apply more force; and tilting the canards forwards, making them into large airbrakes and further pushing the aircraft down.In designing the aircraft, several layouts were studied. Saab ultimately selected an unstable canard layout to give the greatest benefits to performance. The canard configuration gives a high onset of pitch rate and low drag enabling the aircraft to be faster, have longer range, and carry a larger useful payload.Already in operational service with the Swedish Air Force which has ordered 204 aircraft (including 28 dual-seater), the Gripen has also been ordered by the South African Air Force (28 aircraft), Hungary and the Czech Republic (14 aircraft each).

Dassault Mirage F1

The Mirage F1 was designed as the successor of Dassault's Mirage III and Mirage 5. Unlike its predecessors, it has a swept wing mounted high on the fuselage as well as a conventional tail surface.

The first prototype (the development of which was financed by Dassault itself) first flew on 23 December 1966.The type was officially accepted by the French Air Force in May 1967 when three further prototypes were ordered. With the bigger capacity of the SNECMA Atar 9K-50 turbojet with afterburner the F1 easily outclassed the Mirage III.

Having a smaller wingspan than the Mirage III, the F.1 nevertheless proved to be clearly superior to its predecessor. It can carry up to 40-percent more fuel, has a shorter take-off run, a superior range in lo-lo missions, and better maneuverability.

In order to comply to the French Air Force's requirement for an all-weather interceptor, the first production Mirage F1C was equipped with a Thomson-CSF Cyrano IV mono-pulse radar. The later Cyrano IV-1 version added a limited look-down capability.

The Mirage F1 entered service in May 1973 when the first production version was delivered. Initially, the aircraft was only armed with two 30 mm internal cannon, but in 1976 the R530 medium-range air-to-air missile was released for use. A year later the R550 Magic followed. During the same time, the american AIM-9 Sidewinder became part of the Mirage's F1 armament, after the Hellenic Air Force request for its own Mirage F1CG's.

The 79 aircraft of the next production run were delivered during the period March 1977 to December 1983. These were of the Mirage F1C-200 version with a fixed refuelling probe, which required an extension of the fuselage by 7 cm.It served as the main interceptor of the French Air Force until the Mirage 2000 entered service.

F-5E Tiger II

The F-5E was an improved variant of the F-5A "Freedom Fighter" built primarily for foreign military sales. Designed by Northrop in 1953 as a low-maintenance, low-cost fighter, led to a company-financed supersonic trainer called the N-156F Freedom Fighter.Though not purchased by the US military, the government supported the sale of F-5A's to friendly nations. The first contract for the production F-5A was issued in 1962, the first overseas order coming from Norway in February 1964. 836 F-5A/B were built before production ended in 1972. A trainer version, the T-38 Talon, was adopted by the U.S. Air Force, NASA, Turkey and Portugal as a pilot's first introduction to supersonic flight.In 1970 Northrop won a competition for an improved Fighter to replace the F-5A. With more powerful engines, greater fuel capacity, and aerodynamic improvements, the resultant aircraft, initially known as F-5A-21, subsequently became the F-5E. Over 1,400 of the Tigers were made including some purchased by the US Navy and Air Force for use in the Top Gun and Aggressor programs to simulate enemy aircraft and tactics. Various F-5 versions remain in service with many nations. The most advanced are those of Singapore re-designated F-5S/T and include new radar, updated cockpits with multi-function displays, and compatibility with the Rafael Python and AIM-120 AMRAAM air-to-air missiles. Northrop attempted to develop an advanced version of the F-5E named F-20 Tigershark, similar in performance to the F-16. In the end, some 2,700 F-5 aircraft were built for the US and 30 other nations by the time production ceased in 1987. Data for F-5E